Imaging of the testicle: the painful scrotum and nonpalpable masses.

Scrotal pain is initially evaluated by color Doppler ultrasonography providing information on the presence or absence of flow within the testis and B Scan imaging providing important complementary information about lesions such as torsion of the appendix testis and testicular abscess. While radioisotope scanning provides similar information to color Doppler about testicular flow, it does not demonstrate the anatomy. Testicular imaging is extremely sensitive for "silent masses" and useful to evaluate palpable ones. Characteristic findings may be seen with simple testicular cysts and epidermoid cysts. Homogeneously hyperechoic masses have a variety of etiologies but are virtually always benign. A major limitation of a ultrasonography is the large number of nonneoplastic lesions which may mimic tumors.